SFI SYSTEM, Diagnostic DTC:P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308

DTC Code	DTC Name
P0300	Random / Multiple Cylinder Misfire Detected
P0301	Cylinder 1 Misfire Detected
P0302	Cylinder 2 Misfire Detected
P0303	Cylinder 3 Misfire Detected
P0304	Cylinder 4 Misfire Detected
P0305	Cylinder 5 Misfire Detected
P0306	Cylinder 6 Misfire Detected
P0307	Cylinder 7 Misfire Detected
P0308	Cylinder 8 Misfire Detected

DESCRIPTION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause an increase in exhaust emission levels. High concentrations of HC can also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the TWC. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the TWC reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire exceeds the threshold levels and may cause emission deterioration, the ECM illuminates the MIL and sets a DTC.

DTC No.	DTC Detection Condition	Trouble Area
P0300	Simultaneous misfiring of several cylinders detected (2 trip detection logic) Misfire occurs that may damage the three-way catalytic converter (MIL blinks when detected immediately) Emission deterioration misfire occurs (MIL illuminates)	Open or short in engine wire harness Connector connection Vacuum hose connections Ignition system Injector for direct injector Injector for port injector Fuel pressure Mass Air Flow (MAF) meter Engine Coolant Temperature (ECT) sensor Compression pressure Valve clearance Valve timing Ventilation valve and hose Ventilation hose connections Air induction system ECM
P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308	Misfiring of specific cylinder detected (2 trip detection logic) Misfire occurs that may damage the three-way catalytic converter (MIL blinks when detected immediately) Emission deterioration misfire occurs (MIL illuminates)	Open or short in engine wire harness Connector connection Vacuum hose connections Ignition system Injector for direct injector Injector for port injector Fuel pressure Mass Air Flow (MAF) meter Engine Coolant Temperature (ECT) sensor Compression pressure Valve clearance Valve timing Ventilation valve and hose Ventilation hose connections Air induction system ECM

DTC No.

DTC Detection Condition

Trouble Area

P0300

Simultaneous misfiring of several cylinders detected

(2 trip detection logic)

Misfire occurs that may damage the three-way catalytic converter (MIL blinks when detected immediately)
Emission deterioration misfire occurs (MIL illuminates)

Open or short in engine wire harness
Connector connection
Vacuum hose connections
Ignition system
Injector for direct injector
Injector for port injector
Fuel pressure
Mass Air Flow (MAF) meter
Engine Coolant Temperature (ECT) sensor
Compression pressure
Valve clearance
Valve timing
Ventilation valve and hose
Ventilation hose connections
Air induction system
ECM

P0301

P0302

P0303

P0304

P0305

P0306

P0307

P0308

Misfiring of specific cylinder detected

(2 trip detection logic)

Misfire occurs that may damage the three-way catalytic converter (MIL blinks when detected immediately)
Emission deterioration misfire occurs (MIL illuminates)

Open or short in engine wire harness
Connector connection
Vacuum hose connections
Ignition system
Injector for direct injector
Injector for port injector
Fuel pressure
Mass Air Flow (MAF) meter
Engine Coolant Temperature (ECT) sensor
Compression pressure
Valve clearance
Valve timing
Ventilation valve and hose
Ventilation hose connections
Air induction system
ECM

If DTCs that indicate misfires are set for different cylinders, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set when several misfiring cylinders are detected at the same time.

MONITOR DESCRIPTION


*1	Camshaft Angle Sensor Plate
*2	Camshaft Position Sensor
*3	Crank Angle Sensor Plate
*4	Crankshaft Position Sensor (36-2 teeth)

The ECM illuminates the MIL (immediate detection logic) and sets a DTC (2 trip detection logic) when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 10 to 50 misfires per 1000 crankshaft revolutions) occurs once.
After the first 1000 crankshaft revolutions, an excessive misfiring rate (approximately 10 to 50 misfires per 1000 crankshaft revolutions) occurs 4 times in sequential crankshaft revolutions.

The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected (2 trip detection logic):

In every 200 crankshaft revolutions at a high engine rpm, the threshold misfiring percentage is recorded once.
In every 200 crankshaft revolutions at a normal engine rpm, the threshold misfiring percentage is recorded 3 times.

CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Record the DTC(s) and freeze frame data.
Read the misfire counts of each cylinder (Cylinder #1 Misfire Count to Cylinder #8 Misfire Count) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.

Drive the vehicle several times with the conditions, such as engine rpm and engine load, shown in Misfire RPM and Misfire Load in the Data List.

Tech Tips

In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, using the Misfire RPM and Misfire Load in the Data List.

Engine RPM	Duration
Idling	8.0 minutes or more
1000	4.5 minutes or more
2000	2.5 minutes or more
3000	1.5 minute or more

Check whether misfires have occurred by checking DTCs and freeze frame data.

Tech Tips

Do not turn the engine switch off until the stored DTC(s) and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTC(s), freeze frame data and other data will be erased.
Record the DTC(s), freeze frame data and misfire counts.
Turn the engine switch off and wait for at least 5 seconds.

CAUTION / NOTICE / HINT

Tech Tips

If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.
If the misfire still cannot be reproduced even though the conditions stored in the ECM as freeze frame data have been reproduced, one of the following factors is considered to be a possible cause of the problem:

There was insufficient fuel in the tank.
Improper fuel is used.
The spark plugs have been contaminated.
The problem requires further diagnosis.

After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #8 Misfire Count).
Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern after finishing repairs.
For 6 and 8 cylinder engines, the ECM intentionally does not set the specific misfiring cylinder DTCs at high engine RPM. If misfires occur only in high engine RPM areas, only DTC P0300 is set.

In the event of DTC P0300 being present, perform the following operations:

Clear the DTC Click here.
Start the engine and conduct the confirmation driving pattern.
Read the misfiring rates of each cylinder or DTC(s) using the GTS.
Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not set.

When one of Short FT #1, Long FT #1, Short FT #2 or Long FT #2 in the freeze frame data is outside the range of +/-20%, the air-fuel ratio may be Rich (-20% or less) or Lean (+20% or more).
When the Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfire occurred only while warming up the engine.
An extremely imbalanced drive wheel, which causes body vibration, may cause misfire DTCs detection.

PROCEDURE

CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS)

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Trouble Codes.

Read DTCs.

Result
Display (DTC output)	Proceed to
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308	A
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 and other DTCs	B

Tech Tips

If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.

GO TO DTC CHART Click here

CHECK VENTILATION HOSE (HOSE CONNECTIONS)

OK

Ventilation hose is connected correctly and is not damaged.

NG
REPAIR OR REPLACE VENTILATION HOSE Click here

OK
READ VALUE USING GTS (MISFIRE RPM AND MISFIRE LOAD)
1. Connect the GTS to the DLC3.
2. Turn the engine switch on (IG) and turn the GTS on.
3. Enter the following menus: Powertrain / Engine / Data List / Misfire / Misfire RPM and Misfire Load.
4. Read and note the Misfire RPM and Misfire Load values.
  
  Tech Tips
  
  The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.
NEXT

OK
Ventilation hose is connected correctly and is not damaged.

CHECK MISFIRE COUNT OF PORT INJECTION

Clear DTCs Click here.
Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Port. (Procedure "A")
Allow the engine to idle.

Monitor all of the misfire count values that are displayed on the GTS: Powertrain / Engine / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")

Move the gear selector lever to the D position.
Repeat procedure "A" to "B" above.

Monitor all of the misfire count values that are displayed on the GTS.

Result
Misfire count	Proceed to
1 or 2 cylinders have misfire counts	A
3 cylinders or more have misfire counts	A
There are no misfire counts	B

CHECK MISFIRE COUNT OF DIRECT INJECTION Click here

CHECK MISFIRE COUNT OF DIRECT INJECTION

Clear DTCs Click here.
Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Direct. (Procedure "A")
Allow the engine to idle.

Monitor all of the misfire count values that are displayed on the GTS: Powertrain / Engine / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")

Move the gear selector lever to the D position.
Repeat procedure "A" to "B" above.

Monitor all of the misfire count values that are displayed on the GTS.

Result
Misfire Count		Proceed to
Port	Direct	Proceed to
1 or 2 cylinders have misfire counts	1 or 2 cylinders have misfire counts	A
3 cylinders or more have misfire counts	3 cylinders or more have misfire counts	B
1 or 2 cylinders have misfire counts	There are no misfire counts	C
3 cylinders or more have misfire counts	There are no misfire counts	D

CHECK FOR SPARK (SPARK TEST) Click here

REPLACE FUEL INJECTOR FOR PORT INJECTION (MISFIRING CYLINDER) Click here

CHECK FUEL PRESSURE (LOW PRESSURE SIDE) Click here

CHECK SPARK PLUG
1. Inspect the spark plug of the misfiring cylinder Click here.
NG
REPLACE SPARK PLUG Click here

OK
CHECK FOR SPARK (SPARK TEST)
1. Perform a spark test Click here.
  
  Tech Tips
  
  If the result of the spark test is normal, proceed to the next step.
NEXT
CHECK CYLINDER COMPRESSION PRESSURE (MALFUNCTIONING CYLINDER)
1. Measure the cylinder compression pressure of the misfiring cylinder.
  Tech Tips
  - for 2WD Click here.
  - for AWD Click here.
NG
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK
REPLACE ECM Click here
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leakage.
  
  OK
  
  No leakage from air induction system.
NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK

OK
No leakage from air induction system.

READ VALUE USING GTS (COOLANT TEMP)

Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.

Read the Data List twice, when the engine is both cold and warmed up.

Standard
With cold engine
Same as ambient air temperature.
With warm engine
Between 75°C and 95°C (167°F and 203°F).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

READ VALUE USING GTS (MAF SENSOR 1 AND MAF SENSOR 2)
1. Enter the following menus: Powertrain / Engine / Data List / Primary / Engine Speed, Coolant Temp, MAF Sensor 1 and MAF Sensor 2.
2. Allow the engine to idle until the ECT reaches 75°C (167°F) or higher.
3. Read MAF Sensor 1 and MAF Sensor 2 with the engine speed at 2000 rpm.
  
  Standard
  
  Between 2.4 to 12.8 g/s (shift lever is in N position and A/C is OFF)
NG
CHECK HARNESS AND CONNECTOR Click here

OK
CHECK VALVE TIMING
*a Timing Mark
1. Remove the cylinder head cover bank 1 and bank 2.
2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.
3. Rotate the crankshaft pulley and align its notch to timing mark 0 of the timing chain cover. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.
  
  OK
  
  Timing marks on camshaft timing gears are aligned as shown in the illustration.
4. Reinstall the cylinder head cover.
OK
REPLACE ECM Click here

NG
ADJUST VALVE TIMING Click here
CHECK FUEL PRESSURE (LOW PRESSURE SIDE)
1. Check the fuel pressure (low pressure side) Click here.
OK
REPLACE FUEL INJECTOR FOR PORT INJECTION Click here

NG
CHECK FUEL PUMP OPERATION
1. Check the fuel pump operation Click here.
NG
REPLACE FUEL PUMP Click here

OK
CHECK AND REPLACE FUEL SYSTEM (PRESSURE REGULATOR, PIPE LINE AND FILTER)

Standard
Between 2.4 to 12.8 g/s (shift lever is in N position and A/C is OFF)

*a	Timing Mark

OK
Timing marks on camshaft timing gears are aligned as shown in the illustration.

CHECK MISFIRE COUNT OF DIRECT INJECTION

Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Direct. (Procedure "A")
Allow the engine to idle.

Monitor all of the misfire count values that are displayed on the GTS: Powertrain / Engine / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")

Move the gear selector lever to the D position.
Repeat procedure "A" to "B" above.

Monitor all of the misfire count values that are displayed on the GTS.

Result
Misfire Count		Proceed to
Port	Direct	Proceed to
There are no misfire counts	There are no misfire counts	A
There are no misfire counts	There are misfire counts	B

REPLACE FUEL INJECTOR FOR DIRECT INJECTION (MISFIRING CYLINDER) Click here

CHECK MISFIRE COUNT

Clear DTCs Click here.
Enter the following menus: Powertrain / Engine / Data List / All Data / Misfire RPM, Misfire Load, Cylinder #1 Misfire Count to Cylinder #8 Misfire Count and Injection Way.
Drive the vehicle with Misfire RPM and Misfire Load.

Monitor all of the misfire count values or DTCs and Injection Way displayed on the GTS.

Result
Misfire count	Injection Way	Proceed to
There are no misfire counts	-	A
1 or 2 cylinders have misfire counts	Either	B
3 cylinders or more have misfire counts	Either	C
There are misfire counts	Direct	D

CHECK FOR INTERMITTENT PROBLEMS Click here

CHECK SPARK PLUG Click here

CHECK AIR INDUCTION SYSTEM Click here

REPLACE FUEL INJECTOR FOR DIRECT INJECTION (MALFUNCTIONING CYLINDER INJECTOR) Click here

CHECK HARNESS AND CONNECTOR
1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter and ECM Click here.
  
  Tech Tips
  
  Repair any problems.
NEXT

CHECK WHETHER DTC OUTPUT RECURS

Clear the DTCs Click here.
Turn the engine switch off.
Turn the engine switch on (IG) and turn the GTS on.
Start the engine and warm it up.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

Check the DTC judgment result.

Result
Display (DTC Output)	Proceed to
ABNORMAL (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308 output)	A
NORMAL (No DTC output)	B

END

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the E13 or E22 MAF meter connector.
Disconnect the E1 ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open)

Tester Connection	Condition	Specified Condition
E13-1 (VG) - E1-25 (VG)	Always	Below 1 Ω
E13-2 (E2G) - E1-24 (E2G)	Always	Below 1 Ω
E22-1 (VGR) - E1-23 (VG2)	Always	Below 1 Ω
E22-2 (EVGR) - E1-32 (E2G2)	Always	Below 1 Ω

Standard resistance (Check for short)

Tester Connection	Condition	Specified Condition
E13-1 (VG) or E1-25 (VG) - Body ground	Always	10 kΩ or higher
E22-1 (VGR) or E1-23 (VG2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE MASS AIR FLOW METER (BANK 1 AND/OR BANK 2)
1. Replace the mass air flow meter (bank 1 and/or bank 2) Click here.
  
  Tech Tips
  
  If the results of the inspections performed in steps 14 indicated no problem, proceed to the next step without replacing the mass air flow meter.
NEXT

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs Click here.
Turn the engine switch off.
Turn the engine switch on (IG) and turn the GTS on.
Start the engine and warm it up.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

Check the DTC judgment result.

Result
Display (DTC Output)	Proceed to
NORMAL (No DTC output)	A
ABNORMAL (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308 output)	B

END

REPLACE ECM Click here